- Sexually active females of childbearing potential must have a negative serum pregnancy test result at screening. These subjects must use a medically acceptable method of contraception while receiving protocol-assigned product, and are expected to continue to use this method of contraception for up to 90 days following the last dose of the study medication. A woman of childbearing potential is defined as one who is biologically capable of becoming pregnant; including perimenopausal women who are less than 2 years from their last menses.